I have enjoyed frugality and efficiency for several reasons.
First, I really enjoy the simplicity of everything. My 1,100 square foot house has very little wasted space, wasted material items, etc. We only have things we enjoy here, and I find my home to be a very positive environment. Friends with similar incomes have much bigger houses, much higher car payments, and much higher bills. It costs them a lot of working hours just to cover all this.
Second, I like having a long term goal to work towards. Sometimes it's hard to be at work and think it's all mindless and without a purpose; but when you have a goal as big as financial independence, it gives me a real sense of what I'm ultimately working towards.
Probably most importantly, it has given me tremendous leverage that a lot of people just don't have. My wife and I gross about $11,000 per month, yet our expenses are just $2,600 per month. Thus, when we have a kid, cash flow from just my income will be more than enough, and my wife can stay home as long as she wants. Similarly, if/when an emergency happens, we have money set aside to take care of it.
On this last point, when you have that much financial security, it's easy to forget how much people struggle with those types of things. My brother had to work 80+ hours a week when his wife stayed him for their first kid. My friends (both teachers) had to do some side jobs to cover mom staying home to take care of their child. My other brother had to ask my mom for money when he wrecked his car.
Basically, having this much financial security is a pretty darn good feeling, and far outweighs the neuroticism that may come along with being a little overly frugal.